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CHXII01:THE SOLID STATE

318881 Three elements $A, B$ and $C$ crystallise into a cubic solid lattice. Atom $A$ occupy the corners, $B$ atom, the cube centres and $C$ atom, the edge. The formula of the compound is

1

ABC

2

AB C_{2}

3

AB C_{3}

4

AB C_{4}

Explanation:

Number of atoms of $A$ per unit cell $= 8 \times \frac{1}{8} (at the corners) = 1$
Number of atoms of $B$ per unit cell $= 1$ (at the centre) $= 1$
Number of atoms of $C$ per unit cell
$= 12 \times \frac{1}{4} ($ at the edge centre $) = 3$
So, formula of compound is $AB C_{3} .$

CHXII01:THE SOLID STATE

318882 A solid has a structure in which ' $W$ ' atoms are located at the corners of a cubic lattice, ' $O$ ' atoms at the centre of edges and ' $Na$ ' atoms at the centre of the cube. The formula of the compound is

1

{NaWO}_{2}

2

{NaWO}_{3}

3

{Na}_{2} {WO}_{3}

4

{NaWO}_{4}

Explanation:

In a unit cell, atoms (W) at the corner
$= \frac{1}{8} \times 8 = 1$
atoms $(O)$ at the centre of edges
$= \frac{1}{4} \times 12 = 3$
atoms $(Na)$ at the centre of the cube $= 1$ $W : O : Na = 1 : 3 : 1$ , hence, formula is ${NaWO}_{3}$

CHXII01:THE SOLID STATE

318883 Unit cell of ${Fe}_{3} O_{4}$ (ferrous ferrite) has $32 O^{2 -}$ ions in the unit cell. Then the unit cell of ${Fe}_{3} O_{4}$ has :

1

16 {Fe}^{2 +}

ions

2

8 {Fe}^{3 +}

ions

3

16 {Fe}^{3 +}

ions and

8 {Fe}^{2 +}

ions

4 None of these

Explanation:

${Fe}_{3} O_{4}$ contains ${Fe}^{2 +}, {Fe}^{3 +}$ and $O^{2 -}$ ions. To maintain electrical neutrality $16 {Fe}^{+ 3}$ and $8 {Fe}^{2 +}$ ions must be present along with $32 O^{2 -}$ ions.

CHXII01:THE SOLID STATE

318884 In face-centred cubic lattice, a unit cell is shared equally by how many unit cells?

1 6

2 4

3 2

4 8

CHXII01:THE SOLID STATE

318885 A substance $A_{X} B_{Y}$ crystallises in a face centred cubic (fcc) lattice in which atoms ' $A$ ' occupy each corner of the cube and atoms ' $B$ ' occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{X} B_{Y}$ :

1

A_{4} B_{3}

2

A_{3} B

3

{AB}_{3}

4 Composition cannot be specified

Explanation:

Effective number of corner atom
$(A) = 8 \times \frac{1}{8} = 1 = X$
Effective number of face center atom
$(B) = \frac{1}{2} \times 6 = 3 = Y$
Thus, composition of substance $= A B_{3}$ .

CHXII01:THE SOLID STATE

318881 Three elements $A, B$ and $C$ crystallise into a cubic solid lattice. Atom $A$ occupy the corners, $B$ atom, the cube centres and $C$ atom, the edge. The formula of the compound is

1

ABC

2

AB C_{2}

3

AB C_{3}

4

AB C_{4}

Explanation:

Number of atoms of $A$ per unit cell $= 8 \times \frac{1}{8} (at the corners) = 1$
Number of atoms of $B$ per unit cell $= 1$ (at the centre) $= 1$
Number of atoms of $C$ per unit cell
$= 12 \times \frac{1}{4} ($ at the edge centre $) = 3$
So, formula of compound is $AB C_{3} .$

CHXII01:THE SOLID STATE

318882 A solid has a structure in which ' $W$ ' atoms are located at the corners of a cubic lattice, ' $O$ ' atoms at the centre of edges and ' $Na$ ' atoms at the centre of the cube. The formula of the compound is

1

{NaWO}_{2}

2

{NaWO}_{3}

3

{Na}_{2} {WO}_{3}

4

{NaWO}_{4}

Explanation:

In a unit cell, atoms (W) at the corner
$= \frac{1}{8} \times 8 = 1$
atoms $(O)$ at the centre of edges
$= \frac{1}{4} \times 12 = 3$
atoms $(Na)$ at the centre of the cube $= 1$ $W : O : Na = 1 : 3 : 1$ , hence, formula is ${NaWO}_{3}$

CHXII01:THE SOLID STATE

318883 Unit cell of ${Fe}_{3} O_{4}$ (ferrous ferrite) has $32 O^{2 -}$ ions in the unit cell. Then the unit cell of ${Fe}_{3} O_{4}$ has :

1

16 {Fe}^{2 +}

ions

2

8 {Fe}^{3 +}

ions

3

16 {Fe}^{3 +}

ions and

8 {Fe}^{2 +}

ions

4 None of these

Explanation:

${Fe}_{3} O_{4}$ contains ${Fe}^{2 +}, {Fe}^{3 +}$ and $O^{2 -}$ ions. To maintain electrical neutrality $16 {Fe}^{+ 3}$ and $8 {Fe}^{2 +}$ ions must be present along with $32 O^{2 -}$ ions.

CHXII01:THE SOLID STATE

318884 In face-centred cubic lattice, a unit cell is shared equally by how many unit cells?

1 6

2 4

3 2

4 8

CHXII01:THE SOLID STATE

318885 A substance $A_{X} B_{Y}$ crystallises in a face centred cubic (fcc) lattice in which atoms ' $A$ ' occupy each corner of the cube and atoms ' $B$ ' occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{X} B_{Y}$ :

1

A_{4} B_{3}

2

A_{3} B

3

{AB}_{3}

4 Composition cannot be specified

Explanation:

Effective number of corner atom
$(A) = 8 \times \frac{1}{8} = 1 = X$
Effective number of face center atom
$(B) = \frac{1}{2} \times 6 = 3 = Y$
Thus, composition of substance $= A B_{3}$ .

CHXII01:THE SOLID STATE

318881 Three elements $A, B$ and $C$ crystallise into a cubic solid lattice. Atom $A$ occupy the corners, $B$ atom, the cube centres and $C$ atom, the edge. The formula of the compound is

1

ABC

2

AB C_{2}

3

AB C_{3}

4

AB C_{4}

Explanation:

Number of atoms of $A$ per unit cell $= 8 \times \frac{1}{8} (at the corners) = 1$
Number of atoms of $B$ per unit cell $= 1$ (at the centre) $= 1$
Number of atoms of $C$ per unit cell
$= 12 \times \frac{1}{4} ($ at the edge centre $) = 3$
So, formula of compound is $AB C_{3} .$

CHXII01:THE SOLID STATE

318882 A solid has a structure in which ' $W$ ' atoms are located at the corners of a cubic lattice, ' $O$ ' atoms at the centre of edges and ' $Na$ ' atoms at the centre of the cube. The formula of the compound is

1

{NaWO}_{2}

2

{NaWO}_{3}

3

{Na}_{2} {WO}_{3}

4

{NaWO}_{4}

Explanation:

In a unit cell, atoms (W) at the corner
$= \frac{1}{8} \times 8 = 1$
atoms $(O)$ at the centre of edges
$= \frac{1}{4} \times 12 = 3$
atoms $(Na)$ at the centre of the cube $= 1$ $W : O : Na = 1 : 3 : 1$ , hence, formula is ${NaWO}_{3}$

CHXII01:THE SOLID STATE

318883 Unit cell of ${Fe}_{3} O_{4}$ (ferrous ferrite) has $32 O^{2 -}$ ions in the unit cell. Then the unit cell of ${Fe}_{3} O_{4}$ has :

1

16 {Fe}^{2 +}

ions

2

8 {Fe}^{3 +}

ions

3

16 {Fe}^{3 +}

ions and

8 {Fe}^{2 +}

ions

4 None of these

Explanation:

${Fe}_{3} O_{4}$ contains ${Fe}^{2 +}, {Fe}^{3 +}$ and $O^{2 -}$ ions. To maintain electrical neutrality $16 {Fe}^{+ 3}$ and $8 {Fe}^{2 +}$ ions must be present along with $32 O^{2 -}$ ions.

CHXII01:THE SOLID STATE

318884 In face-centred cubic lattice, a unit cell is shared equally by how many unit cells?

1 6

2 4

3 2

4 8

CHXII01:THE SOLID STATE

318885 A substance $A_{X} B_{Y}$ crystallises in a face centred cubic (fcc) lattice in which atoms ' $A$ ' occupy each corner of the cube and atoms ' $B$ ' occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{X} B_{Y}$ :

1

A_{4} B_{3}

2

A_{3} B

3

{AB}_{3}

4 Composition cannot be specified

Explanation:

Effective number of corner atom
$(A) = 8 \times \frac{1}{8} = 1 = X$
Effective number of face center atom
$(B) = \frac{1}{2} \times 6 = 3 = Y$
Thus, composition of substance $= A B_{3}$ .

CHXII01:THE SOLID STATE

318881 Three elements $A, B$ and $C$ crystallise into a cubic solid lattice. Atom $A$ occupy the corners, $B$ atom, the cube centres and $C$ atom, the edge. The formula of the compound is

1

ABC

2

AB C_{2}

3

AB C_{3}

4

AB C_{4}

Explanation:

Number of atoms of $A$ per unit cell $= 8 \times \frac{1}{8} (at the corners) = 1$
Number of atoms of $B$ per unit cell $= 1$ (at the centre) $= 1$
Number of atoms of $C$ per unit cell
$= 12 \times \frac{1}{4} ($ at the edge centre $) = 3$
So, formula of compound is $AB C_{3} .$

CHXII01:THE SOLID STATE

318882 A solid has a structure in which ' $W$ ' atoms are located at the corners of a cubic lattice, ' $O$ ' atoms at the centre of edges and ' $Na$ ' atoms at the centre of the cube. The formula of the compound is

1

{NaWO}_{2}

2

{NaWO}_{3}

3

{Na}_{2} {WO}_{3}

4

{NaWO}_{4}

Explanation:

In a unit cell, atoms (W) at the corner
$= \frac{1}{8} \times 8 = 1$
atoms $(O)$ at the centre of edges
$= \frac{1}{4} \times 12 = 3$
atoms $(Na)$ at the centre of the cube $= 1$ $W : O : Na = 1 : 3 : 1$ , hence, formula is ${NaWO}_{3}$

CHXII01:THE SOLID STATE

318883 Unit cell of ${Fe}_{3} O_{4}$ (ferrous ferrite) has $32 O^{2 -}$ ions in the unit cell. Then the unit cell of ${Fe}_{3} O_{4}$ has :

1

16 {Fe}^{2 +}

ions

2

8 {Fe}^{3 +}

ions

3

16 {Fe}^{3 +}

ions and

8 {Fe}^{2 +}

ions

4 None of these

Explanation:

${Fe}_{3} O_{4}$ contains ${Fe}^{2 +}, {Fe}^{3 +}$ and $O^{2 -}$ ions. To maintain electrical neutrality $16 {Fe}^{+ 3}$ and $8 {Fe}^{2 +}$ ions must be present along with $32 O^{2 -}$ ions.

CHXII01:THE SOLID STATE

318884 In face-centred cubic lattice, a unit cell is shared equally by how many unit cells?

1 6

2 4

3 2

4 8

CHXII01:THE SOLID STATE

318885 A substance $A_{X} B_{Y}$ crystallises in a face centred cubic (fcc) lattice in which atoms ' $A$ ' occupy each corner of the cube and atoms ' $B$ ' occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{X} B_{Y}$ :

1

A_{4} B_{3}

2

A_{3} B

3

{AB}_{3}

4 Composition cannot be specified

Explanation:

Effective number of corner atom
$(A) = 8 \times \frac{1}{8} = 1 = X$
Effective number of face center atom
$(B) = \frac{1}{2} \times 6 = 3 = Y$
Thus, composition of substance $= A B_{3}$ .

CHXII01:THE SOLID STATE

318881 Three elements $A, B$ and $C$ crystallise into a cubic solid lattice. Atom $A$ occupy the corners, $B$ atom, the cube centres and $C$ atom, the edge. The formula of the compound is

1

ABC

2

AB C_{2}

3

AB C_{3}

4

AB C_{4}

Explanation:

Number of atoms of $A$ per unit cell $= 8 \times \frac{1}{8} (at the corners) = 1$
Number of atoms of $B$ per unit cell $= 1$ (at the centre) $= 1$
Number of atoms of $C$ per unit cell
$= 12 \times \frac{1}{4} ($ at the edge centre $) = 3$
So, formula of compound is $AB C_{3} .$

CHXII01:THE SOLID STATE

318882 A solid has a structure in which ' $W$ ' atoms are located at the corners of a cubic lattice, ' $O$ ' atoms at the centre of edges and ' $Na$ ' atoms at the centre of the cube. The formula of the compound is

1

{NaWO}_{2}

2

{NaWO}_{3}

3

{Na}_{2} {WO}_{3}

4

{NaWO}_{4}

Explanation:

In a unit cell, atoms (W) at the corner
$= \frac{1}{8} \times 8 = 1$
atoms $(O)$ at the centre of edges
$= \frac{1}{4} \times 12 = 3$
atoms $(Na)$ at the centre of the cube $= 1$ $W : O : Na = 1 : 3 : 1$ , hence, formula is ${NaWO}_{3}$

CHXII01:THE SOLID STATE

318883 Unit cell of ${Fe}_{3} O_{4}$ (ferrous ferrite) has $32 O^{2 -}$ ions in the unit cell. Then the unit cell of ${Fe}_{3} O_{4}$ has :

1

16 {Fe}^{2 +}

ions

2

8 {Fe}^{3 +}

ions

3

16 {Fe}^{3 +}

ions and

8 {Fe}^{2 +}

ions

4 None of these

Explanation:

${Fe}_{3} O_{4}$ contains ${Fe}^{2 +}, {Fe}^{3 +}$ and $O^{2 -}$ ions. To maintain electrical neutrality $16 {Fe}^{+ 3}$ and $8 {Fe}^{2 +}$ ions must be present along with $32 O^{2 -}$ ions.

CHXII01:THE SOLID STATE

318884 In face-centred cubic lattice, a unit cell is shared equally by how many unit cells?

1 6

2 4

3 2

4 8

CHXII01:THE SOLID STATE

318885 A substance $A_{X} B_{Y}$ crystallises in a face centred cubic (fcc) lattice in which atoms ' $A$ ' occupy each corner of the cube and atoms ' $B$ ' occupy the centres of each face of the cube. Identify the correct composition of the substance $A_{X} B_{Y}$ :

1

A_{4} B_{3}

2

A_{3} B

3

{AB}_{3}

4 Composition cannot be specified

Explanation:

Effective number of corner atom
$(A) = 8 \times \frac{1}{8} = 1 = X$
Effective number of face center atom
$(B) = \frac{1}{2} \times 6 = 3 = Y$
Thus, composition of substance $= A B_{3}$ .